Comparison of glycoprotein B (gB)–specific peak immunoglobulin G (IgG) binding antibody and neutralizing antibody responses. A, Soluble gB-specific total IgG antibody titers (left panel) and relative avidity index (RAI) (right panel) were compared between the 2 vaccine cohorts. B, TB40/E virion-bound IgG titers (left panel) and RAI (right panel) were also compared between the 2 vaccine cohorts. C, Similarly, Towne (left panel) and Merlin gB (right panel) cell-associated IgG antibody responses were compared among the 2 vaccine cohorts. D, The epithelial neutralizing antibody against AD169r in ARPE-19 cells (left panel) and fibroblast neutralizing antibody against AD169r (middle panel) and Towne (right panel) in HFF-1 cells were compared between the mRNA-1647 and gB/MF59 vaccine cohorts. Additionally, the human cytomegalovirus (HCMV)–infected individuals were also included for the comparison. Open blue circles denote the seropositive samples at baseline from the mRNA-1647 vaccine cohort while open purple circles denote the in-house HCMV-seropositive individuals in some assays to increase the statistical power. However, the statistical analysis indicated that the increased sample number did not change the conclusion. P values from nonparametric t tests are reported (Mann–Whitney test). ***P < .001. Abbreviations: ED50, 50% effective dose; gB, glycoprotein B; ID50, 50% inhibitory dose; IgG, immunoglobulin G; MFI, mean fluorescense intensity; S+, human cytomegalovirus seropositive.
